Abstract

Femtosecond-laser-driven terahertz (THz) electromagnetic pulses have been used to study the carrier transport dynamics of bulk semiconductors¹ and modulation-doped GaAs quantum wells² by observing absorption spectra. Using a Drude fit to the absorption measurement results,¹ carrier density and mobility have been obtained. We apply this technique to noncontact investigation of the carrier dynamics of metal-oxide-semiconductor (MOS) inversion layers. The inversion layer mobility is typically obtained through the drain current measurements versus drain voltage for a given gate voltage. This method therefore requires a full MOS transistor structure, including source and drain. The THz technique only requires a simple MOS capacitor to determine the mobility.

© 1996 Optical Society of America